...conversion of foreign currency is to be made is a matter of substance and is governed by lex contractus, i.e, the law of the contract, and not by lex fori, i.e, the law of the forum. It has been urged...contract construed in accordance with the proper law of the contract and the money of payment is determined by the law of the country in which such debt or liability is payable i.e lex loci solutionis. (See...conversion may be treated as one relating to the mode of performance and, consequently, subject to the lex loci solutionis. The decision on the second point, however, is liable to encroach severely...